Post operative adhesions represent a major problem in patients recovering from surgery. When organs and tissues are subject to surgical and related trauma, there is a tendency for adhesions to form between the affected areas and neighboring tissue.
In the case of intestinal surgery, the incidence of adhesions causing intestinal obstructions has been reported as approximately four times that due to strangulated hernia. The post operative formation or reformation of pelvic adhesions is reported to be a major factor contributing to the relatively poor results obtained in infertility surgery.
Various methods have been suggested for reducing the incidence of peritoneal adhesions following surgical intervention, but results have not been entirely favorable. One method involves the application of chemical treating agents to the site of the surgical incision or abrasion in an effort to inhibit the physiological response responsible for the formation of the fibrous tissue which comprises the adhesion mass. In this category are enzymes such as fibrinolysin and papase, polyphloretinphosphate, oxyphenbutazone, a mixture of phenylbutazone and prednisolone, polyvinylpyrrolidone and dextran.
A second approach to preventing the formation of adhesions is to install a physical barrier material between the site of the surgical activity and the neighboring tissue where adhesions are most expected to occur. In this category are silicone sheets such as Silastic*, a medical grade silicone elastomer available from Dow Corning, Gelfilm*, an absorbable gelatin film available from Upjohn, and Surgicel*, a knit fabric of oxidized regenerated cellulose (ORC) available from Johnson & Johnson Products, Inc.
The results obtained with the prior art materials and methods have varied according to different investigators. In the case of oxidized cellulose, for example, very good results were reported by Larssen, Acta Chir Scand 144: pp. 375-378 (1978) and Raftery, Br. J. Surg. Vol. 67 pp. 57-58 (1980); negative results were obtained by Schroder, Acta Chir Scand 148 pp. 595-596 (1982), Yemini, Int. J. Fertil 29 pp. 194-196 (1984) and Soules, Am. J. Obstet & Gyn, Vol. 143 pp. 829-834 (1982); and mixed results were obtained by Nishimura, Jpn. J. Surg. vol. 13 pp. 159-163 (1983).
In the copending U.S. patent application of Linsky and Cunningham, Ser. No. 768,280, filed Aug. 22, 1985, entitled "Method and Material for Prevention of Surgical Adhesions", the teachings of which are specifically incorporated herein by reference, a particular fabric construction was disclosed resulting in an improved adhesion barrier fabric. That material was a fabric of oxidized regenerated cellulose (ORC) characterized by having a porosity as defined by open area of 12 to 20 percent and a density of from about 8 to 15 mg/cm.sup.2. A typical fabric is prepared from 60 denier, 18 filament bright rayon yarn knitted on a 32 gauge 2 bar warp knitting machine. The knit fabric is oxidized using conventional procedures as described for example in U.S. Pat. No. 3,364,200.
ORC fabrics constructed in accordance with the invention of the aforesaid copending patent application have demonstrated superior performance in reducing the incidence of postoperative adhesion formation when compared to fabrics of ORC previously available.
The above fabric was effective in reducing the incidence of postoperative adhesions when positioned as a physical barrier between the site of the surgical activity and neighboring tissue, but further improvement is still possible. Test results using a preferred version of the above fabric, called TC-7, in adhesion reduction in a rabbit uterine horn model, established its ease of handling. It proved simple to apply, conformed well to the structure, adhered in place, and substantially absorbed within two weeks after surgery.